AGKICULTURaL CHEMISTEY AGROTECHNY. ^ 207 



but when tested qualitatively with zinc aud sulphuric acid, a dark brown stain 

 is obtained upon lead acetate paper. This coloration is due to organic bodies. 



To determine fusel oil in distilled liquors, H. P. Bassett {Jour. Indus, and 

 Engin. Clicm., 2 {1910), No. 9, pv. 389, 390).— This method is a modification of 

 the Savelle method, and is as follows: 



" To 25 cc. sample add 5 cc. of a normal alkali solution and digest for 1 hour 

 on the water bath under a reflux condenser to saponify the esters, then connect 

 with a suitable distilling apparatus aud distill 25 cc. ; add 5 cc. of water and 

 distill an additional 5 cc. To this distillate add 0.2 gm. of >u-phenylenediamin 

 hydrochlorid and boil under a reflux condenser for 1 hour to remove the alde- 

 hydes, after which distill, collecting 25 cc. ; add 5 cc. of water and distill an 

 additional 5 cc, bringing the distillate up to the original volume. To this dis- 

 tillale add slowly an erpial volume of [pure] ILSOi concentrated, heat nearly to 

 boiling, and while still hot add 5 to 10 drops of a 1 : 1000 solution of furfural; 

 a pink or rod color will develop in the presence of the higher alcohols, which 

 may be compared with a standard solution of amyl alcohol treated in the same 

 manner. By this method less than 0.01 per cent of fusel oil can be determined 

 and 1 part in 20,000 detected." 



The chemical and bacteriological methods for examining milk, G. RuiiM 

 {Zlschr. FIcisch u. Milrliln/!/.. 21 (1910), Xos. 1, pp. l.',-19; 2, pp. -',7-51; 3. pp. 

 78-83). — This is a description vnd critical discussion of the various bacterio- 

 logical and chemical methods for examining milk. Their value to the voteri- 

 nai'y profession is particularly considered. 



The control of the milk supply and milk examination, 11. Luiikk; and 

 L. Kressneb {Molk. Ztg. [IlUdrshcim], 25 {1911), No. //, pp. 1,7-50).— The 

 authors point out that the value of the calcium chlorid serum test (E. S. II., 2.3, 

 p. 30!)) is greatly dependent upon the system of milk control which is in vogue 

 tn the community where it is to be applied. They first discuss the various 

 factors which influence the fat, etc., content of milk, and then give their results 

 of a study made in regard to such influencing factors. 



They report that sodium l)icarbonate. borax, boracic acid, and sodium chro- 

 mate, in concentrations ranging from 0.005 to 0.1 per cent in aqueous solutions, 

 have no influence on the refraction. Formalin has an influence, as when over 

 0.3 cc. were present a slight increase in refraction could be noted, but not in 

 the amounts in which it is employed as a milk preservative. " Sodium bicar- 

 bonate did not even show an effect when 0.1 per cent was added. On the other 

 hand, boracic acid, borax, and sodium chromate began to show their influence 

 wnth concentrations ranging from 0.08 to 0.1 per cent. Salicylic acid when pres- 

 ent shows itself as an additional refraction, and with as small an amount as 0.05 

 per cent in an aqueous or milk solution. It is used in this quantity as a pre- 

 servative. 



As a result of examining normal milks the authors found the greatest devi- 

 ation in the morning milks to be 1.3 scale divisions, in afternoon milks 1.05 

 divisions, and in evening milks 1.5 scale divisions. 



Examination of milk, E. Ackermann (Abs. in Chem. Ztg., 31, {1910), No. 

 115. p. 1021f). — The author constructed an apparatus for preparing calcium 

 chlorid milk serum, which will enable those who do not possess a refracto- 

 meter to calculate the refractive index of a calcium chlorid milk serum from the 

 specific gravity figure. A table for this purpose is appended. The author does 

 not believe that this method can supplant the refractometer entirely. 



The electrical conductivity of milk and the application of this principle 



for detecting the addition of water and the addition of electrolytes, R. 



BiNAGHi {Rev. Gen. Lalt, 8 {1910), No. 18, pp. 417-^25; 8 {1911), No. 19, pp. 



J,33-J,Jf9). — It appears from this work that an absolutely fresh and pure milk 



104861°— No. 3—11 2 



